The most serious effect of periodontal disease is alveolar bone resorption. Loss of bone from the alveolar ridge results in loss of teeth affecting 23 million Americans. This research proposes a study using an animal model to attempt to determine the relative importance of local factors in causing or enhancing bone resorption. Questions to be asked are: Is local bone resorption to be expected if bone resorption inducing agents are present in the intact gingival sulcus? Is penetration of the gingival sulcus necessary before alveolar bone is resorbed? Is there an effect on bone resorption at sites distant from the local installation of the test substance? What is the effect of repeated injections into the gingival sulcus (simulating chronic periodontal disease)? If it is found that local agents induce or enhance bone resorption, can local or systemic counter-agents reverse the process? Answers to these questions would provide a set of criteria for beginning bone resorption which would be a valuable adjunct to present research methods. This model has proved useful in immunological studies but has never been applied to an evaluation of bone resorption.